Numerous methods have been developed to teach visual discriminations to individuals with intellectual disabilities. For many individuals, these methods have proven very successful. For some individuals, however, directing attention to task-relevant features of stimuli has proven difficult or impossible using these methods. The challenges facing researchers are to identify the bases of these failures and to design teaching methods that are maximally effective for particular individuals and/or populations (e.g., Down syndrome, autism). One of the main determinants of the success of these visually based teaching methods is the visual selective attention skills of the learner. If individuals or groups have differing visual processing skills and/or tendencies, then teaching effectiveness may vary as well. For example, those with autism have been reported to have exceptionally good visual discrimination skills (O'Riordan & Plaisted, 2001), even when compared to chronological-age-matched peers. However, these enhanced abilities may result in attention to irrelevant aspects of a visual presentation and, therefore, interfere with learning. Those with Down syndrome, on the other hand, tend to demonstrate selective attention skills that are poorer than mental-age-matched comparison groups (Munir, Cornish, &Wilding, 2000). They are slower to detect targets of visual search and demonstrate a unique pattern of errors on these tasks. Thus, individuals with autism and Down syndrome demonstrate unique patterns of visual analysis strengths and weaknesses. These basic skills must be considered when designing teaching programs for these populations. A "one-size-fits-all" approach will not be effective. This project addresses these challenges directly by providing an in-depth analysis of visual search skills in populations (i.e., those with autism, those with Down syndrome) likely to differ dramatically in how they direct and focus attention on components of visual stimuli. Further, this basic research will be used to develop teaching procedures that match the abilities of the individual/population so that learning occurs quickly and with few errors. We will: (1) assess sensitivities to critical dimensions for object discrimination (color and form) and letter/number discrimination (e.g., line orientation, curvature) in populations with autism, Down syndrome, mixed-etiology mental retardation, and no intellectual disability (MA-matched);(2) assess visual search skills in complex visual arrays within which multiple dimensions (e.g., color and form) vary simultaneously. In these arrays, multiple dimensions and features compete for attention;and (3) design teaching procedures that match the unique visual processing profiles of these populations. PERSONNEL ENGAGED ON PROJECT, INCLUDING CONSULTANTS/COLLABORATORS. Usecontinuation pages as needed to provide the required information in the format shown below on all individuals participating in the project. Principal Investigator: Michael Carlin, Assistant Professor of Psychiatry, UMMS Shriver Center Co- Investigator: Richard Serna, Assistant Professor of Psychiatry, UMMS Shriver Center Page 115 Studies of Stimulus Control in Mental Retardation Mcllvane, William J. Project 1: Carlin &Serna A. SPECIFIC AIMS Numerous methods have been developed to teach visual discriminations to individuals with intellectual disabilities. For many individuals, these methods have proven very successful. For some individuals, however, directing attention to task-relevant features of stimuli has proven difficult or impossible using these methods. The challenges facing researchers are to identify the bases of these failures and to design teaching methods that are maximally effective for particular individuals and/or populations (e.g., Down syndrome, autism). One of the main determinants of the success of these visually based teaching methods is the visual selective attention skills of the learner. If individuals or groups have differing visual processing skills and/or tendencies, then teaching effectiveness may vary as well. For example, those with autism have been reported to have exceptionally good visual discrimination skills (O'Riordan &Plaisted, 2001), even when compared to chronological-age-matched peers. However, these enhanced abilities may result in attention to irrelevant aspects of a visual presentation and, therefore, interfere with learning. Those with Down syndrome, on the other hand, tend to demonstrate selective attention skills that are poorer than mental-age-matched comparison groups (Munir, Cornish, &Wilding, 2000). They are slower to detect targets of visual search and demonstrate a unique pattern of errors on these tasks. Thus, individuals with autism and Down syndrome demonstrate unique patterns of visual analysis strengths and weaknesses. These basic skills must be considered when designing teaching programs for these populations. A "one-size-fits-all" approach will not be effective. This project addresses these challenges directly by providing an in-depth analysis of visual search skills in populations (i.e., those with autism, those with Down syndrome) likely to differ dramatically in how they direct and focus attention on components of visual stimuli. Further, this basic research will be used to develop teaching procedures that match the abilities of the individual/population so that learning occurs quickly and with few errors. The specific aims of this project, therefore, are to: (1) assess sensitivities to critical dimensions for object discrimination (color and form) and letter/number discrimination (e.g., line orientation, curvature) in populations with autism, Down syndrome, mixed-etiology mental retardation, and no intellectual disability (MA-matched). This component of the project will provide a comprehensive analysis of dimension-specific discrimination skills in these populations. Existing literature, though limited, implies that these populations would be expected to perform quite differently on these tasks. Further, our use of reaction time (RT) and eye-tracking measures of